Scroll type compressor having a pressure chamber opposite a discharge port

ABSTRACT

Spiral fixed scroll teeth ( 2   a ) project from an end plate ( 2   b ) of a fixed scroll ( 2 ), and spiral movable scroll teeth ( 4   a ) project from an end plate ( 4   b ) of a movable scroll ( 4 ). The end plate ( 4   b ) of the movable scroll ( 4 ) is provided with a discharge port ( 8 ) for discharging compressed refrigerant gas. A pressure chamber ( 16 ) is provided on the back surface of the end plate ( 2   b ). A port ( 10 ) communicating with the pressure chamber ( 16 ) is provided on a position of the end plate ( 2   b ) opposed to the discharge port ( 8 ). Thus obtained is a scroll compressor reducing pulsation when discharging a fluid by feeding the compressed fluid into the pressure chamber.

TECHNICAL FIELD

The present invention relates to a scroll compressor, and moreparticularly, it relates to a scroll compressor reducing pulsationcaused when discharging a compressed high-pressure fluid.

BACKGROUND ART

As an example of a conventional scroll compressor, an in-shaft dischargetype scroll compressor discharging compressed high-pressure refrigerantgas into a casing through a passage provided in a drive shaft drivingthe compressor is now described.

As shown in FIG. 4, a partition 125 separates a closed casing 101 into asuction chamber 123 and a discharge chamber 122.

The suction chamber 123 is provided therein with a scroll compressionmechanism 103 for sucking and compressing refrigerant gas.

The scroll compression mechanism 103 is formed by a fixed scroll 110 anda movable scroll 111. Spiral fixed scroll teeth 110 b project from anend plate 110 a of the fixed scroll 110. Spiral movable scroll teeth 111b project from an end plate 111 a of the movable scroll 111. The movablescroll teeth 111 b fit with the fixed scroll teeth 110 b thereby forminga compression chamber 114.

A suction port 110 c is provided on a side surface of the fixed scroll110 for feeding low-pressure refrigerant gas received from a suctionpipe 105 into the compression chamber 114. A discharge port 111 c isprovided on a portion around the center of the end plate 111 a of themovable scroll 111 for discharging the refrigerant gas compressed to ahigh-pressure state.

The discharge chamber 122 stores a motor 107. The scroll compressionmechanism 103 is driven through a crank part 130 provided on the upperend of a drive shaft 108 of the motor 107. The drive shaft 108 isprovided with a discharged gas passage 108 e for guiding the refrigerantgas discharged from the discharge port 111 c to a discharged gas outlet108 f provided on the lower end of the drive shaft 108.

The suction pipe 105 for feeding the refrigerant gas into the scrollcompression mechanism 103 is connected to a portion of the casing 101closer to the suction chamber 123. A discharge pipe 106 for dischargingthe high-pressure refrigerant gas from the casing 101 is connected to aportion of the casing 101 closer to the discharge chamber 122.

Operation of the aforementioned scroll compressor is now described.

Rotation of the motor 107 is transmitted to the scroll compressionmechanism 103 through the drive shaft 108 and the crank part 130. Thus,the movable scroll 111 revolves with respect to the fixed scroll 110.The compression chamber 114 formed by the movable scroll teeth 111 b andthe fixed scroll teeth 110 b contractedly moves from the outerperipheral portion toward the central potion due to the revolution ofthe movable scroll 111.

Thus, the low-pressure refrigerant gas fed from the suction pipe 105into the compression chamber 114 through the suction port 110 c iscompressed to a high-pressure state and discharged from the dischargeport 111 c of the movable scroll 111.

The high-pressure refrigerant gas discharged from the discharge port 111c passes through the discharged gas passage 108 e provided on the driveshaft 108 and flows out into the discharge chamber 122 from thedischarged gas outlet 108 f. The high-pressure refrigerant gas flowingout into the discharge chamber 122 passes through a clearance betweenthe motor 107 and the casing 101 or the like and is delivered from thecasing 101 through the discharge pipe 106.

However, the aforementioned scroll compressor has the followingproblems:

The compression chamber 114 formed by the movable scroll teeth 111 b andthe fixed scroll teeth 110 b spirally moves from the outer peripheralportion toward the central portion following revolution of the movablescroll 111. At this time, the refrigerant gas compressed in thecompression chamber 114 is discharged from the discharge port 111 c,whereafter the refrigerant gas compressed in a next compression chamberis discharged.

The scroll compression mechanism 103 intermittently performs suchdischarge along with revolution of the movable scroll 111, and hence itfollows that the discharged refrigerant gas pulsates. The pulsatingrefrigerant gas may vibrate the drive shaft 108 particularly whenpassing through the discharged gas passage 108 f.

Depending on operating conditions of the scroll compressor, further, thenatural frequency of the drive shaft 108 may resonate with the vibrationfrequency of the pulsation to make noise.

DISCLOSURE OF INVENTION

The present invention has been proposed in order to solve theaforementioned problems, and an object thereof is to provide a scrollcompressor suppressing vibration or noise by suppressing pulsation ofdischarged gas.

A scroll compressor according to the present invention comprises a firstscroll, a second scroll, a discharge port, a pressure chamber and aport. The first scroll has a first spiral body projecting from an endplate. The second scroll has a second spiral body projecting from an endplate for fitting with the first spiral body and forming a compressionchamber. The discharge port is provided on the end plate of one of thefirst and second scrolls. The pressure chamber is provided on the backsurface of the other one of the first and second scrolls. The port isprovided on the end plate of the other scroll to communicate with thepressure chamber.

This scroll compressor, suppressing pulsation of a fluid compressed inthe compression chamber by introducing the fluid into the pressurechamber, can suppress vibration or noise following such pulsation.

Preferably, the pressure chamber is formed by the other scroll and alid.

In this case, it is possible to prevent pulsation of the fluid flowinginto the pressure chamber from directly influencing a casing of thescroll compressor.

Preferably, the scroll compressor further comprises a relief portprovided on the end plate of the other scroll for guiding a fluid in theprocess of compression to the pressure chamber and a relief valveopening/closing the relief port.

In this case, the relief valve is open when the pressure of the fluid inthe compression chamber in the process of compression exceeds thepressure in the pressure chamber for feeding the fluid from thecompression chamber in the process of compression into the pressurechamber, so that the pressure of the compression chamber in the processof compression is not increased beyond the pressure in the pressurechamber but over-compression is suppressed while the difference betweenthe pressure of the compression chamber immediately before communicatingwith the discharge port and a discharge pressure is reduced andpulsation of the discharged fluid can be more suppressed when thecompression chamber communicates with the discharge port. The timing forfeeding the fluid into the pressure chamber through the relief valvedeviates from the timing for discharging the fluid from the dischargeport, thereby leveling the pressure of the fluid and reducing pulsationthereof.

More preferably, the discharge port communicates with a passage providedin a drive shaft for driving the first scroll or the second scroll.

In this case, vibration of the drive shaft or the like can beeffectively suppressed in the so-called in-shaft discharge type scrollcompressor having a drive shaft formed with a passage for passing afluid therethrough.

Preferably, the first scroll is a fixed scroll, the second scroll is amovable scroll, and the port is provided on the fixed scroll.

In this case, the pressure chamber and the port communicating with thepressure chamber are formed on the side of the fixed scroll, whereby thepressure chamber and the port can be more readily formed as comparedwith the case of forming the same on the side of the movable scroll.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a partially fragmented longitudinal sectional view of a scrollcompressor according to a first embodiment of the present invention;

FIG. 2 is a partially fragmented longitudinal sectional view of a scrollcompressor according to a second embodiment of the present invention;

FIG. 3 is a partially fragmented longitudinal sectional view of a scrollcompressor according to a third embodiment of the present invention; and

FIG. 4 is a partially fragmented longitudinal sectional view of aconventional scroll compressor.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

A scroll compressor according to a first embodiment of the presentinvention is now described.

As shown in FIG. 1, a scroll compression mechanism 1 for sucking andcompressing refrigerant gas is provided in a closed casing 20. Thescroll compression mechanism 1 is formed by a fixed scroll 2 and amovable scroll 4. A spiral body (hereinafter referred to as “fixedscroll teeth 2 a”) projects from an end plate 2 b of the fixed scroll 2.

A spiral body (hereinafter referred to as “movable scroll teeth 4 a”)projects from an end plate 4 b of the movable scroll 4. The movablescroll teeth 4 a fit with the fixed scroll teeth 2 a thereby forming acompression chamber 29.

The scroll compression mechanism 1 is arranged on a framework 6, andparticularly the fixed scroll 2 is fixed to the framework 6 with a bolt3 or the like.

A suction pipe 18 for feeding refrigerant gas into the scrollcompression mechanism 1 is connected to an upper portion of the casing20. A discharge pipe (not shown) foe delivering high-pressurerefrigerant gas from the casing 20 is connected to a side surface of thecasing 20.

A suction port 21 is provided on the outer peripheral side of the fixedscroll 2 for feeding low-pressure refrigerant gas received from thesuction pipe 18 into the compression chamber 29. A discharge port 8 isformed on a portion around the center of the end plate 4 b of themovable scroll 4 for discharging the refrigerant gas compressed to ahigh-pressure state.

The casing 20 stores a motor (not shown) in its lower portion. Thescroll compression mechanism 1 is driven through a crank part 30provided on the upper end of a drive shaft 5 of the motor. A crankchamber 7 provided on the framework 6 stores the crank part 30. Thedrive shaft 5 is provided with a discharged gas passage 5 a for guidingthe refrigerant gas discharged from the discharge port 8 to a dischargedgas outlet (not shown) provided on the lower end of the drive shaft 5.

In this scroll compressor, a pressure chamber 16 is provided on the backsurface of the scroll not provided with the discharge port 8, i.e., thefixed scroll 2 in particular. The end plate 2 b of the fixed scroll 2opposed to the discharge port 8 is provided with a port 10 guiding thedischarged refrigerant gas to the pressure chamber 16. The pressurechamber 16 is formed by the fixed scroll 2 and a lid 17.

The scroll compressor is further provided with a relief port 12 forpreventing over-compression in compression, a relief valve 14opening/closing the relief port 12 and a valve guard 14 a regulatinglifting of the relief valve 14.

The relief port 12 connects the compression chamber 29 in the process ofcompression with the pressure chamber 16. The relief valve 14 and thevalve guard 14 a are arranged in the pressure chamber 16, and fixed tothe back surface of the fixed scroll 2 with a bolt 15.

The scroll compressor according to this embodiment has theaforementioned structure.

Operation of the aforementioned scroll compressor is now described.

Rotation of the motor 107 is transmitted to the scroll compressionmechanism 1 through the drive shaft 5 and the crank part 30, and themovable scroll 4 revolves with respect to the fixed scroll 2. Thecompression chamber 29 formed by the movable scroll teeth 4 a and thefixed scroll teeth 2 a contractedly moves from the outer peripheralportion toward the central portion due to such revolution of the movablescroll 4.

Thus, the low-pressure refrigerant gas fed from the suction pipe 18 intothe compression chamber 29 through the suction port 21 is compressed.The refrigerant gas compressed to a high-pressure state is dischargedfrom the discharge port 8 of the movable scroll 4.

The high-pressure refrigerant gas discharged from the discharge port 8passes through the discharged gas passage 5 a provided on the driveshaft 5 and flows out into the casing 20 through the discharged gasoutlet (not shown) provided on the lower end of the drive shaft 5. Thehigh-pressure refrigerant gas flowing out into the casing 20 isdelivered from the casing 20 through the discharge pipe.

In such serial operation of the scroll compressor, the high-pressurerefrigerant gas discharged from the discharge port 8 partially flowsinto the pressure chamber 16 through the port 10 provided on theposition opposed to the discharge port 8.

Thus, as compared with the case where the high-pressure refrigerant gasdirectly flows from the discharge port 8 into the discharged gas passage5 a, the refrigerant gas partially flowing into the pressure chamber 16is inhibited from pulsation so that vibration of the drive shaft 5 canbe suppressed. Further, it is also possible to prevent the naturalfrequency of the drive shaft 5 from resonating with the vibrationfrequency of the pulsation and making noise.

Depending on the operating situation, the fluid pressure in thecompression chamber 29 in the process of compression may exceed thepressure of the discharge port 8 or the discharge pipe. In other words,the compression chamber 29 may cause over-compression.

When the pressure of the refrigerant gas in the compression chamber 29in the process of compression exceeds the pressure of the pressurechamber 16, it follows that the relief valve 14 is open so that therefrigerant gas in the process of compression in the compression chamber29 flows into the pressure chamber 16 through the relief port 12.

Thus, the pressure of the compression chamber 29 in the process ofcompression is not increased beyond the pressure in the pressure chamber16 but over-compression is suppressed while the difference between thepressure of the compression chamber 29 immediately before communicatingwith the discharge port 8 and a discharge pressure is so reduced thatpulsation of the discharged refrigerant gas can be more suppressed whenthe compression chamber 29 communicates with the discharge port 8.

Further, the timing for feeding the refrigerant gas into the pressurechamber 16 through the relief valve 14 deviates from the timing fordischarging the same from the discharge port 8, thereby leveling thepressure of the refrigerant gas and reducing pulsation thereof.

In this scroll compressor, the pressure chamber 16 and the port 10 arearranged on the side of the fixed scroll 2, whereby these elements canbe more readily formed.

The pressure chamber 16 is formed by the fixed scroll 2 and the lid 17so that pulsation of the refrigerant gas can be prevented from directtransmission to the casing 20 and the suction pipe 18 can be preventedfrom overheat due to the provision of the lid 17.

Second Embodiment

A scroll compressor according to a second embodiment of the presentinvention is now described.

As shown in FIG. 2, a pressure chamber 16 is formed on the back surfaceof a movable scroll 4 in the scroll compressor according to thisembodiment. In other words, the pressure chamber 16 is provided in acrank chamber 7 provided on a framework 6 for storing a crank part 30 ofthe movable scroll 4.

Therefore, a port 10 is formed around the center of the movable scroll4, while a drive shaft 5 and a boss portion 4 c are formed with a cavity9 a and passages 9 b and 9 c for guiding high-pressure refrigerant gasto the pressure chamber 16. A sealing mechanism 11 for sealing thepressure chamber 16 is provided between the framework 6 and the driveshaft 5.

An end plate 4 b of the movable scroll 4 is provided with a relief port12 for preventing over-compression in compression, a relief valve 14opening/closing this relief port 12 and a valve guard 14 a regulatinglifting of the relief valve 14.

The relief port 12 connects a compression chamber 29 in the process ofcompression with the pressure chamber 16. The relief valve 14 and thevalve guard 14 a are arranged in the pressure chamber 16 and fixed tothe back surface of the movable scroll 4 with a bolt 15.

On the other hand, a fixed scroll 2 is provided with a discharge port 8for discharging compressed high-pressure refrigerant gas. A dome 20 a isprovided with a discharge pipe 19 for delivering the dischargedrefrigerant gas from a casing 20.

The remaining structure of this scroll compressor is identical to thatof the scroll compressor shown in FIG. 1 described with reference to thefirst embodiment. Therefore, components of the scroll compressoraccording to the second embodiment identical to those shown in FIG. 1are denoted by the same reference numerals, and redundant description isnot repeated.

Operation of the aforementioned scroll compressor is now described.

Following rotation of the drive shaft 5, the movable scroll 4 revolveswith respect to the fixed scroll 2. The compression chamber 29 formed bymovable scroll teeth 4 a and fixed scroll teeth 2 a contractedly movesfrom the outer peripheral portion toward the central portion due to therevolution of the movable scroll 4.

Thus, low-pressure refrigerant gas fed from a suction pipe 18 into thecompression chamber 29 through a suction pot 21 is compressed to ahigh-pressure state and discharged from the discharge port 8 of thefixed scroll 2. The high-pressure refrigerant gas discharged from thedischarge port 8 is delivered from the casing 20 from the discharge pipe19 mounted on the dome 20 a through a space in the dome 20 a.

In such serial operation of the scroll compressor, the high-pressurerefrigerant gas discharged from the discharge port 8 partially passesthrough the port 10 provided on a position opposed to the discharge port8 and flows into the pressure chamber 16 through the cavity 9 a and thepassages 9 b and 9 c.

Thus, as compared with the case where the high-pressure refrigerant gasdirectly flows from the discharge port 8 into the space in the dome 20a, the refrigerant gas partially flowing into the pressure chamber 16 isinhibited from pulsation and the dome 20 a as well as the casing 20 canbe inhibited from transmission of vibration.

When the pressure of the refrigerant gas in the compression chamber 29in the process of compression exceeds the pressure of the pressurechamber 16, it follows that the relief valve 14 is open so that therefrigerant gas in the process of compression in the compression chamber29 flows into the pressure chamber 16 through the relief port 12,similarly to the case of the first embodiment.

Thus, the pressure of the compression chamber 29 in the process ofcompression is not increased beyond the pressure in the pressure chamber16 but over-compression is suppressed while the difference between thepressure of the compression chamber 29 immediately before communicatingwith the discharge port 8 and a discharge pressure is so reduced thatpulsation of the discharged refrigerant gas can be more suppressed whenthe compression chamber 29 communicates with the discharge port 8.

Further, the timing for feeding the refrigerant gas into the pressurechamber 16 through the relief valve 14 deviates from the timing fordischarging the same from the discharge port 8, thereby leveling thepressure of the refrigerant and reducing pulsation thereof.

Third Embodiment

A scroll compressor according to a third embodiment of the presentinvention is now described.

As shown in FIG. 3, the scroll compressor according to this embodimentis the so-called co-rotating scroll compressor having two scrolls 22 and24 rotating together. In other words, the drive scroll 22 rotatesfollowing rotation of a drive shaft 22 c while the follower scroll 24revolves with respect to the drive scroll 22 through a coupling 26.

Spiral drive scroll teeth 22 a project from an end plate 22 b of thedrive scroll 22. Spiral follower scroll teeth 24 a project from an endplate 24 b of the follower scroll 24. The follower scroll teeth 24 a fitwith the drive scroll teeth 22 a thereby forming a compression chamber29.

The drive scroll 22 is provided with a discharge port 8 for dischargingcompressed high-pressure refrigerant gas. A pressure chamber 16 isformed in the follower scroll 24 on the side of the back surface of theend plate 24 b. The end plate 24 b of the follower scroll 24 opposed tothe discharge port 8 is formed with a port 10 guiding the dischargedrefrigerant gas to the pressure chamber 16.

The end plate 24 b of the follower scroll 24 is further provided with arelief port 12 for preventing over-compression in compression, a reliefvalve 14 opening/closing the relief port 12 and a valve guard 14 aregulating lifting of the relief valve 14.

The relief port 12 connects the compression chamber 29 in the process ofcompression with the pressure chamber 16. The relief valve 14 and thevalve guard 14 a are arranged in the pressure chamber 16 and fixed tothe end plate 24 b with a bolt 15.

The drive shaft 22 c is provided with a discharged gas passage 22 d forguiding the refrigerant gas discharged from the discharge port 8 to adischarged gas outlet (not shown) provided on the side of the lower endof the drive shaft 22 c. A casing 20 is provided with a discharge pipe19 for delivering the discharged refrigerant gas from the casing 20.

Operation of the aforementioned scroll compressor is now described.

The drive scroll 22 rotates following rotation of the drive shaft 22 c.Following rotation of the drive scroll 22, the follower scroll 24revolves with respect to the drive scroll 22 through the coupling 26.The compression chamber 29 formed by the drive scroll teeth 22 a and thefollower scroll teeth 24 a contractedly moves from the outer peripheralportion toward the central portion due to the revolution of the followerscroll 24.

Thus, low-pressure refrigerant gas fed from a suction pipe 18 into thecompression chamber 29 through a suction pot 21 is compressed to ahigh-pressure state and discharged from the discharge port 8 of thedrive scroll 22. The high-pressure refrigerant gas discharged from thedischarge port 8 flows out into the casing 20 through the gas dischargeport (not shown) provided on the side of the lower end of the driveshaft 22 c through the discharged gas passage 22 d formed in the driveshaft 22 c. The refrigerant gas flowing out into the casing 20 isdelivered from the casing 20 from the discharge pipe 19 mounted on thecasing 20.

In such serial operation of the scroll compressor, the refrigerant gascompressed in the compression chamber 29 partially flows into thepressure chamber 16 through the port 10 when discharged.

Thus, as compared with the case where the high-pressure refrigerant gasdirectly flows from the discharge port 8 into the discharged gas passage22 d, the refrigerant gas partially flowing into the pressure chamber 16is inhibited from pulsation and the drive shaft 22 c can be inhibitedfrom vibration. Further, the natural frequency of the drive shaft 22 ccan be prevented from resonating with the vibration frequency ofpulsation and making noise.

When the pressure of the refrigerant gas in the compression chamber 29in the process of compression exceeds the pressure of the pressurechamber 16, it follows that the relief valve 14 is open so that therefrigerant gas in the process of compression in the compression chamber29 flows into the pressure chamber 16 through the relief port 12,similarly to the case of the first embodiment.

Thus, the pressure of the compression chamber 29 in the process ofcompression is not increased beyond the pressure in the pressure chamber16 but over-compression is suppressed while the difference between thepressure of the compression chamber 29 immediately before communicatingwith the discharge port 8 and a discharge pressure is so reduced thatpulsation of the discharged refrigerant gas can be more suppressed whenthe compression chamber 29 communicates with the discharge port 8.

Further, the timing for feeding the refrigerant gas into the pressurechamber 16 through the relief valve 14 deviates from the timing fordischarging the same from the discharge port 8, thereby leveling thepressure of the refrigerant gas and reducing pulsation thereof.

The scroll compressor according to the present invention is particularlyeffective for suppressing vibration of a drive shaft or reducing noisefollowing resonance particularly in an in-shaft discharge type scrollcompressor as shown in the first or third embodiment.

The present invention is effectively applied to a structure forsuppressing pulsation in a scroll compressor discharging a compressedhigh-pressure fluid.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

We claim:
 1. A scroll compressor comprising: a first scroll having afirst spiral body projecting from an end plate; a second scroll having asecond spiral body projecting from an end plate for fitting with saidfirst spiral body and forming a compression chamber; a discharge portprovided on said end plate of one of said first and second scrolls, saiddischarge port communicating with a passage provided in a drive shaftfor driving said first scroll or said second scroll; a pressure chamberprovided on the back surface of the other one of said first and secondscrolls; and a port provided on said end plate of said other scroll tocommunicate with said pressure chamber, wherein said port is positionedsubstantially opposed to said discharge port and wherein said port issubstantially straight through said end plate of said other scroll alonga direction of extension of the drive shaft.
 2. The scroll compressoraccording to claim 1, wherein said pressure chamber is formed by saidother scroll and a lid.
 3. The scroll compressor according to claim 1,wherein said first scroll is a fixed scroll, said second scroll is amovable scroll, and said port is provided on said fixed scroll.
 4. Thescroll compressor according to claim 1, wherein said port is positionedsubstantially opposed to said discharge port so as to substantiallyprevent vibration of the drive shaft.
 5. The scroll compressor accordingto claim 1, wherein said port is positioned substantially opposed tosaid discharge port so as to suppress pulsation of a discharged gas. 6.The scroll compressor according to claim 1, further comprising a reliefport provided on said end plate of said other scroll for guiding a fluidin the process of compression to said pressure chamber and a reliefvalve opening/closing said relief port.
 7. The scroll compressoraccording to claim 6, wherein said relief valve comprises a one-wayrelief valve for opening and closing said relief port in response toover pressure in said compression chamber.